| 摘要 |
NEW MATERIAL:Thieno[3,2-b][1,8]naphthyridine-7-carboxylic acid derivatives of formula VI and their salts. EXAMPLE:5-Ethyl-5,8-dihydro-5-oxothieno[3,2-b][1,8]naphthyridine-7-car boxylic acid. USE:Antibiotic: they are effective on Gram-positive and -negative bacteria. PREPARATION:A compound of formula I (R' is lower alkyl) is oxidized with an oxidizing agent such as selenium dioxide to form a compound of formula II. The product is heated together with a thioglycolic ester in the presence of an alkali carbonate to be led to a compound of formula III (R'' is lower alkyl). The partial hydrolysis of the compound of formula III in the presence of an alkali hydroxide gives a compound of formula IV, which is heated in a high-boiling solvent in the presence of coppor or a coppor salt to form a compound of formula V. Finally, the product is hydrolyzed with an acid to produce the compound of formula VI. |
